ref: 83c7a727e05c7280a457bcdf5681f73ce225e0ea
dir: /sys/src/libsec/port/aesCBC.c/
#include "os.h" #include <libsec.h> /* * Define by analogy with desCBCencrypt; AES modes are not standardized yet. * Because of the way that non-multiple-of-16 buffers are handled, * the decryptor must be fed buffers of the same size as the encryptor. */ void aesCBCencrypt(uchar *p, int len, AESstate *s) { uchar *ip, *eip; if(((p-(uchar*)0) & 3) == 0){ for(; len >= AESbsize; len -= AESbsize){ ip = s->ivec; ((u32int*)ip)[0] ^= ((u32int*)p)[0]; ((u32int*)ip)[1] ^= ((u32int*)p)[1]; ((u32int*)ip)[2] ^= ((u32int*)p)[2]; ((u32int*)ip)[3] ^= ((u32int*)p)[3]; aes_encrypt(s->ekey, s->rounds, ip, ip); ((u32int*)p)[0] = ((u32int*)ip)[0]; ((u32int*)p)[1] = ((u32int*)ip)[1]; ((u32int*)p)[2] = ((u32int*)ip)[2]; ((u32int*)p)[3] = ((u32int*)ip)[3]; p += AESbsize; } } else { for(; len >= AESbsize; len -= AESbsize){ ip = s->ivec; for(eip = ip+AESbsize; ip < eip; ) *ip++ ^= *p++; aes_encrypt(s->ekey, s->rounds, s->ivec, s->ivec); memmove(p - AESbsize, s->ivec, AESbsize); } } if(len > 0){ ip = s->ivec; aes_encrypt(s->ekey, s->rounds, ip, ip); for(eip = ip+len; ip < eip; ) *p++ ^= *ip++; } } void aesCBCdecrypt(uchar *p, int len, AESstate *s) { uchar *ip, *eip, *tp; u32int t[4]; if(((p-(uchar*)0) & 3) == 0){ for(; len >= AESbsize; len -= AESbsize){ t[0] = ((u32int*)p)[0]; t[1] = ((u32int*)p)[1]; t[2] = ((u32int*)p)[2]; t[3] = ((u32int*)p)[3]; aes_decrypt(s->dkey, s->rounds, p, p); ip = s->ivec; ((u32int*)p)[0] ^= ((u32int*)ip)[0]; ((u32int*)p)[1] ^= ((u32int*)ip)[1]; ((u32int*)p)[2] ^= ((u32int*)ip)[2]; ((u32int*)p)[3] ^= ((u32int*)ip)[3]; p += AESbsize; ((u32int*)ip)[0] = t[0]; ((u32int*)ip)[1] = t[1]; ((u32int*)ip)[2] = t[2]; ((u32int*)ip)[3] = t[3]; } } else { for(; len >= AESbsize; len -= AESbsize){ tp = (uchar*)t; memmove(tp, p, AESbsize); aes_decrypt(s->dkey, s->rounds, p, p); ip = s->ivec; for(eip = ip+AESbsize; ip < eip; ){ *p++ ^= *ip; *ip++ = *tp++; } } } if(len > 0){ ip = s->ivec; aes_encrypt(s->ekey, s->rounds, ip, ip); for(eip = ip+len; ip < eip; ) *p++ ^= *ip++; } }